Jacob kersten



April 17, 1928, 1,666,571

J. KERSTEN SOUND AMPLIFYING HORN Filed March 28. 1927 5 Sheets-Sheet l mwnor Jacob Kufan 1,666,571 Apnl 17, 1928. Jf KERSTEN SOUND AMPLIFYING HORN Filed March 28, 1927 3 Sheetssheet 2 April 17, 1928.

J. KERSTEN SOUND AMPLI FYING HORN Filed March 28. 1927 5 Sheets-Sheet 5 Invemov JmoobKusYen 13% mM/v Patented Apr. 17, 1928.

UNITED STATES PATENT orifice.

JACOB KERSTEN,- OF KALAMAZOO, .'MICHIGAN.

' 1. "v1.1 'i .Application lduMalrch 28, 1927, Seri.a 1|No.; }78,851.

This invention relates 'to' an ainplijfying horn and .the method; vof .constructing fthe same, :the horn being parti'cularlya'dap'tedl for use Withloud speaker'.units.I I' Itfis an object and purpose vof the; presentginvention' to construct a horn which lhas' an eX'cep tionally long length but Which can be placedz ina small space, the hornnbeing very compact, s o thatgit is very easily ,and readily housed ivithin 'a .vcabinetxvithout the. necessity of constructing an overly; large cabinet l Another purpose, and object of the' invention vfeuilirg.fof th-iirnf, reference may be A.had rto the following description .taken .in connectionI the accompanyingldrawings, in which;

.Fig. l is an. elevation of a completed ain` n lfying horn Amade in accordancewith the inventionqV Fig. v2 ,is an elevation showing-the, two sections. as the horn ilsmade, ilnthe; first iinstance separated fromeach other.

l Fig. 3.is a perspectiieyiew,offtheiinol'd usedA for making one section oftheliorn.-

iFig. ./Lzis'i a ysection, somewhat enlarged,

.Fig. 'is an enlarged fragmentary iieiticul section takensubstantially on :the plane Fig. 6 is a. fragmentary section4 'illustrating the manner in which Athe :various nial method followed in. completing the horn.

Fig. 8 isalongitudinalsetion through the smaller'end section o fI the h ornfshowing how the same is built around: the mold used.

Figs. 9 and 10 are views similar to views e ,and 7 illustrating Substantiallylike steps of thehorn constructionrfor the second smaller sectionthereof, andv l Fi 1l is a perspective View of the sleeve mem er used as a part ofthe hornconstrucand built" up off'aj plurality. off'onnected v-sections?) vand/1, thelatter, 'h'ing-ay reduced part l5 outer end ofsinallerfdianieter than thesniallest end oftheSection. The

manner in which,thefse mold lsectioiilsl are ,se-

cated at, l is placed fthe sanefbeing gof suitable tubular' ffrm-,thatitirnay be dra-Wn and stretched foyerlthelmoldeitending y below the loWer-e'djspf the larger end portiolrl of said mold,A l reduced ,portion 5,. The knitted fabric-as thus, 'strtchledf is opened considerably as is evidenti.. s.. i Vlvftenthe knitted fabric has been placed over y the mold' a, cem'.entitiou's composition, 7, the-principal ingredients of which arefplaster of ,Paris mixed with de Xtrine, vplaced over the'linittedfabric G 'the thickness of. the .composition being Substantially oneeighth of. an inch. When this has. been placed eonipletelyover the fabric 6, a vlayer of b ur'lap 8 is neXt placed over the c ornposition material. rIlhe burlap is net .stretchable and is' cut to ,propery'shape that it may entirely -cover lthe, ceinentitious com posi tion At the nl arge'endl 1 AVofthe 'mold bothtlie fabric 6 andfthelburlap'S'iire extendeddown- War'dly below tlie edges ofthe mold making the depending ends 9, shown. Overtlie burlap a. thickness ofpaper orfpap'ier 'inchlO is next iplaedandcemented in 'position-' When this has .been done, @rectangular ring ,l1 of :proper dimensions ,is :placefdover the form and brought againsttheabnrlap 8 and also beyond theend .of the forcing the same into the cementitious composition 7. This ring, which is made of wire, extends entirely around and closely adjacent the extrcn'ie lower edges oitI the en` largctl end 1 of thc mold. 'l`he depending endsl El ot' the fabric'tl and burlap S are then turned up"\\ardlv and around the ring4 or i'rauic l1 and hack against. the outer side ot' the paper 1t). lt is to he understood that the ceiuentitious composition has sul'licient adhesive properties to cause the burlap to closely adhere thereto but in any case where the material will not of itself adhere, suitable cementing agent-s are used for the purpose. And when the depending end s 9 lof the fabric and burlap are turned under the frame 141 and back upon the paper 1.0 the saine 'are cemented in place. The h'on is then finished by applying `two thicknesses 1Q of suitable tough )a per 'oi'er the 'paper or papier mche 10 angl cementing the lsame in place. The 'paper 12 used is `what is ordinarily known as'red ro'sin paper.

At 'the vend of the mold at which the reduced portion 5 is located, the fabric 6 ce mentitious composition 7, burlap 8, papier mch 10 and sheets 12 conform tocthe shape of the'mold so that the horn has `an end 13 of smaller diameter than the remainder of the horn with a shoulder 14 between it and the :adjacent larger portions. After the horn has dried outfand set in shape the re duced section 13 is inished by san-'ing'a portion of 'the 'same 'oil as'o'n the plane 'of line A-'A. AThe section ofthe 'horn thus made over the mold shown in Eig. 3 is of the shape shown lin loiver part bf 2, .having a large open end or bell 1'6 trom which the horn etends and progressively decreases in size as indicated at 15, terminating in the reducing end 13.

T he remaining section ott thev horn is made in much similar manner. The mold used comprises a series of sections 1T connected together hut capable of ready detachment,

the section 17 ofthe m'ol'd at it's'large'r e'nd havingr a base 18, shown in Fig. 8. The

knitted lfabric '6. cemcntiti'ons composition 7. bui'lap :8, paper or -papier mche'. 10 and the tinal finishing sheets 1Q of red resin paper are 'applied i'n the same way', except that no n'ir'e ring similar to the ring 11 is used anywhere. The projecting ends 19'" of the `fabric 6 and hurlap 8 are turned upwardly Afrom the position -in which they appear in Fig. 9 lying against the upper side 'of the hase 18, an'd cement-'ed against the paper 10 yWithout the use 'of any .reinforcing Ting `or frame. I n v Also at thel opposite s'mal'leijend of the lforni Pbefore the construction 'of this horn section "is started, a Vsleeve 7member 'is placed over `the forni comprising a metal sleeve 19 interiorty threaded at one end and havin-g cnnnect'edhertb fand ."rcing; 'fn-om Iits other "end 'a "relatively ong'ltjapei'cd "slee'e Qt) of thin sheet metal. The tree end portion ol'A the sleeve, Qt) is cut a short distance and adjacent parts turueil outwardly to make anchors 2l over which the knitted fabric t is drawn and which project somewhat into the ceme'ntitious composition T. Sleeve. 2t) is ol metal sufliciently thick that when the horn section is completed its outer surface and the outer surface ot' the linal sheet 12 used fa re `substantially iush.

The second section 03": the horn, the construction 'o'f which 'has just been described, when taken from thepmold, comprises a subsimonly curved pantin 28 tapered portion '24 the rl e`11;'g`th 'of which "is stiiisannaiiyequai-tp are length or che Steeve 20. The .meta'ijsieve '1a may have "are 10aa speakr'unit attached thereto by screw necti'o'n'tvith 'the' l'iiiterioly threaded open free end'ofth'e 'said sleeve. 3 i t The tito sections of the horn when completed are'j'oin'ed together by placing tlietend and "a straight or "the portion '23 over the reducen section 13 ceinenti'ng andjoini'ng the same together in any manner suitable as' by a 'celinetin'g tape, making a joint"suhasindicated'at 25 in Fig. 1. i

1t is evident that the hoi-n may 'be made of various 'shapes and'feoiffigiiatitihs'so"as' to occupy very compact sl'bac'e and atthe :same time having a sufficient length of airtco'lum'nt'o greatly amplity 'son'nd VWaves passing thereto fron a loud sfiealer'ftihift at the small end oftli'e'llibi'i. The -nianiie'r in vhieh the horn is cbnstructed'is "very 'practical and eiiicient. The Vmaterials used 'are cheap, are cemented vtogether 'quickly Aand feas'ily, and when tinished have desired Iacoustic properties for sound amplifying and mo'dulation. The inter'iorfsurface o'f the horn particularly at 4the large end or'lbel-l fthereof .is finished with any snitablef'nishing rnate'rial which `will' completely 'fill 'the pores :of the fabric 6 and make a smooth surface; The outer su'ifa'ce the l'ror'n is fi'nishled by inerely spraying lacquer thereon. Then thus finished the horn is ready for installation in a cabinet. I 7 i The inv'ention is defined in theappe'nded claims 'and is "to be cdns'iderd comprehensive of all fomi's "of structure Ifciniiig within their sc'p-e.

l claim': Y y

1. An amplifying lioin.co1npiising an inner -rigid liod'v "o'f cenen'titious material, sir-etched elastic [fabi-ic on the inner sich. (n the horn inside 'of 4said bdy, inelastic yc'oarse lfzbric 'on the 'onter slide bf Said body, and tongh paper outside 'of aiid coveringV the's'ec- 'ond fabric. j v l 3. An amplifying horn comprising, a rigid body of cementitious material, an inner fabric lining for the body, an outer fabric Covering:r said body :ind paper covering the Cil ner fabric lining, an outer fabric covering for the body, a ring around fglie larger end of the horn wrapped in said fabrics, and paper covering the. outer fal'uii, subst-.f1 ntizil ly :is describe-d.

In testimony whereof I allix my Signature.

JACOB KERSTEN. 

